The present invention relates generally to area and/or volume radiation illumination such as area lighting and specifically to highway lighting and to a lighting device using discrete light sources, such as LEDs, and a method for calculating light and/or wavelength radiation intensity on a target surface and/or surfaces, and/or volume, and/or volumes illuminated by a plurality of light sources.
The present state of LED technology is such that individual LEDs, while very efficient in conversion of electrical energy to light and/or other wavelength radiation generation, produce very small quantities of light. Accordingly, the typical LEDs currently available commercially have not been used for illumination of significant areas, such as highways or runways.
Based on research to illuminate a typical 400 foot section of interstate highway and meeting the existing design requirements of the governing AASHTO Engineering Design Code, the required number of individual LEDs is very large. The present invention is directed to the need for controlling and focusing this very large number of individual point-light sources, from on top of a typical 80 to 160 foot tall, high-mast lighting pole, unto the required section of highway, which may or may not be straight and usually is not a two-dimensional surface, and providing a relatively uniform light intensity across the full length and width of the highway section.
The main structural engineering design limitation of existing highway high-mast lighting poles is the wind load constraint, which is in part a function of the projected surface area of the lamps perched at the top of the pole. Retro-fitting existing poles requires that the replacement illumination equipment not exceed the existing lamp projected surface area. The typical high-mast pole lamp clusters has a projected surface area of 10 square feet. The present invention is directed to a need to provide a lighting device that allows the use of a large number of individual LEDs packaged in such a manner as to have a projected surface area less than that of the lamps being replaced.
Prior art systems for illuminating large, distant areas generally are deficient in that they produce light pollution, confusing night time driving conditions, light trespass, glare, energy waste, high maintenance cost and contribution to urban sky glow. The present invention is directed to a need to provide an area lighting and/or other wavelength radiation device that avoids the shortcomings of the prior art lighting systems. While the terms lighting or light are used herein, the reader will recognize that where appropriate the terms lighting or light could be substituted with any appropriate wavelength radiation.
It is an object of the present invention to provide an area lighting device that controls and focuses a very large number of LEDs from on top of a typical 80 to 160 foot tall, high-mast lighting pole, unto the required section of highway, and provides a relatively uniform light intensity across the full length and width of the highway section.
It is another object of the present invention to provide an area lighting device that can retro-fit existing poles without exceeding the existing lamp projected surface area thereby to stay within the design wind load of the exiting poles.
It is an object of the present invention to provide an area lighting device that provides a light output that minimizes the occurrence of light pollution, generation of confusing driving conditions due to confusing night time lighting patterns, light trespass, glare, energy waste, high maintenance cost and contribution to urban sky glow.
It is another object of the present invention to provide an area lighting and/or other wavelength radiation device that provides a more overall uniform lighting pattern and intensities on the targeted illumination area, surface or space.
It is another object of the present invention to provide an area lighting and/or other wavelength radiation device that provides precise placement of light and/or wavelength radiation intensity in the target area and/or volume.
It is still another object of the present invention to provide an area lighting device that uses relatively narrow angularity LEDS and/or lens covered EL panels that minimizes the total potential light available at any one angle of view thereby reducing the potential amount of light available to glare.
It is another object of the present invention to provide an area lighting device that uses different wavelength LEDs and/or EL panels and/or radiation sources having wavelength intensities different from standard car headlight wavelengths to provide the driver with clearly defined separation between the area lighting provided by the lighting device and the trail-blazing of the driver""s car headlights, allowing the driver to better navigate through complex highway interchanges, ramps, and traffic pattern merging and crossing areas.
It is still another object of the present invention to provide an area lighting device that uses LEDs or ELs whose light output can be maintained at a constant level by use of feedback illumination measuring equipment configurations, thereby reducing the maintenance costs associated with bulb replacement.
It is another object of the present invention to provide an area lighting and/or other wavelength radiation methodology that allows the designer to provide illumination to the target area and restrict the illumination levels of individual light sources to provide the desired light intensity pattern desired within the target area.
It is still another object of the present invention to provide an area lighting and/or other wavelength radiation methodology that allows the designer to create more tightly contrasting light and dark intensities over a large well defined target area and/or volume.
The present invention provides an area lighting device, comprising a plurality of panels arranged into a hollow box having interconnected side walls and open bottom; and at least one of the wall panels comprising a light emitting panel having a lighted side facing inside the hollow box. An advantage to the light-box construction is that radiation sources, such as LED""s, when mounted on a typical circuit-board, tend to radiate more heat on the circuit-board side as opposed to the illumination generation side. That is, in the case of LED""s mounted on a typical circuit-board, a majority of the waste-heat generated originates not on the LED circuit side by rather on the xe2x80x9cbacksidexe2x80x9d of the circuit board. By building the light-box, with xe2x80x9cbacksidexe2x80x9d of the circuit-board panel on the outside of the box, waste-heat is more easily wicked away from both the circuit-board and the LEDs. This is important when using radiation sources such as LEDs because heat-build-up can cause both permanent and temporary light-output degradation and reduced-life-expectancy of the typical LED. The box construction allows free passage of air or other fluids through the box, allowing for waste-heat wicking from the radiation-source side of the circuit-board panels.
The present invention also provides an area lighting device, comprising a plurality of panels arranged into a hollow box having interconnected side walls, open bottom and an enclosing top wall; first, second and third of the side walls panels comprising of different radiation wavelength sources such as red, green and blue light emitting panels and/or different configurations or patterns of different radiation wavelength sources arranged on individual panels, respectively, each having an illuminating side facing inside the hollow box.
The present invention further provides an area lighting device, comprising a first plurality of panels arranged into a first hollow box having interconnected side walls and open top and bottom, at least one of the side wall panels comprising a light emitting panel having a lighted side facing inside the first hollow box; a second plurality of panels arranged into a second hollow box having interconnected side walls and open bottom, at least one of the side wall panels comprising a light emitting panel having a lighted side facing inside the second hollow box; and an enclosure connecting the bottom of the second box to the open top of the first box such that light generated within the second box is transmitted to the first box. The second box need not be physically attached to the first box. Radiation generated within the second box may be directed from the second box to the portal of the first box.
The present invention further provides a street lighting device, comprising a pole; a luminaire disposed at an upper end of the pole; and the luminaire including a plurality of light emitting panels oriented toward the street to provide area lighting.
The present invention also provides a method for calculating the illumination intensity on a target surface and/or volume provided by a plurality of light sources disposed in one location above the target surface, each light source providing a cone of light where the axis of the cone has the highest light intensity and the boundary of the cone represents a percentage (typically 50%) of the wavelength radiation intensity from the center, the method comprising of subdividing the target volume into individual target surfaces; subdividing the target surface into grids; for each grid, calculating the light intensity provided by each light source by taking the cross product of a location vector represented by a line connecting the light source and the grid, and an aiming vector represented by the cone axis; calculating the angle between the location vector and the aiming vector; if the angle is less than one-half the cone angle, calculating the primary lighting intensity at the grid; if the angle is greater than one-half the cone angle, but less than the secondary angle, calculating the secondary light intensity at the grid; plotting the total light intensity at each grid.
The present invention also provides a method for calculating the illumination intensity on a target surface and/or target volume provided by a plurality of radiation sources disposed in a first location removed from the target surface and/or target volume and the interaction of the first radiation intensity pattern with a radiation intensity pattern generated by a plurality of radiation sources disposed in a second location removed from the target surface and/or target volume.
The present invention also provides a method for calculating the illumination intensity on a target surface and/or target volume provided by a plurality of radiation sources disposed in a first location removed from the target surface and/or target volume and the interaction of the first radiation intensity pattern with a radiation intensity pattern generated by a plurality of radiation sources disposed in a second radiation sources"" location target""s surface and/or target""s volume.
These and other objects of the present invention will become apparent from the following detailed description.